800KVA 15KV Oil Immersed Transformer

800kVA 15kV oil immersed transformer is a three-phase power distribution transformer designed to step down medium voltage (15kV class) to usable low voltage levels for industrial, commercial, and utility applications.

It uses transformer oil (mineral or alternative insulating oil) as both an insulating and cooling medium. The oil circulates naturally to dissipate heat generated by the windings, ensuring stable performance under continuous load conditions.

Key characteristics include:

Rated capacity: 800kVA

Primary voltage: 15kV class (commonly 13.8kV / 15kV systems)

Cooling method: Oil-immersed self-cooling (ONAN)

High efficiency and low loss design

Strong overload capability and long service life

It is widely used in power distribution networks where reliability, heat dissipation, and durability are critical.

Factory Testing Standards

Winding Resistance Test

Each unit is tested using a DC resistance tester and a double-arm bridge to check winding resistance. This ensures there are no defects in manufacturing or loose connections inside the 800kVA 15kV oil immersed transformer.

Voltage Ratio & Phase Shift Verification

A transformer ratio tester, industrial frequency power supply, and voltmeter are used to confirm that primary and secondary voltage ratios match the design values and that the vector group connection is correct.

Short-Circuit Impedance & Load Loss Test

Short-circuit testing is carried out to verify impedance characteristics and load losses. This ensures the transformer performance meets design and operational requirements.

No-Load Loss & No-Load Current Test

With the secondary side open and rated voltage applied to the primary side, no-load loss and current are measured to confirm compliance with agreed performance data.

After all tests are completed, a factory test report is issued for each unit. Any non-conforming item is reworked and retested.

GUANGBIAN maintains strict quality control to ensure every transformer leaves the factory fully tested and ready for reliable long-term operation.

GUANGBIAN Transformer Factory Test Equipment

DC Resistance Tester

Kelvin bridge

Transformer Ratio Tester and Adjustable Power-frequency Voltage Regulating Power Supply

Excitation Transformer and Multi-frequency Power Generator

GUANGBIAN Transformer Comprehensive Testing Workshop

Technical Document 

Our Factory

Sheet metal workshop

Foil winding workshop

Winding workshop

Winding oven workshop

Transformer assembly workshop

Transformer commissioning workshop

FAQ

Q1: What is the main function of an 800kVA 15kV transformer?

It steps down medium-voltage electricity (15kV class) to low-voltage levels suitable for end-user consumption in industrial and commercial systems.

Q2: Why use an oil-immersed transformer instead of dry type?

Oil-immersed transformers provide:

● Better heat dissipation

● Higher overload capacity

● Longer insulation life

● Lower operational losses under heavy load

They are preferred for outdoor and high-capacity applications.

Q3: Is this transformer suitable for outdoor installation?

Yes. Oil-immersed transformers are designed for outdoor use with sealed tanks, corrosion protection, and weather-resistant construction.

Q4: What maintenance is required?

Routine maintenance includes:

● Oil level and oil quality checks

● Insulation resistance testing

● Temperature monitoring

● Bushing and terminal inspection

Q5: Can it handle overload conditions?

Yes, short-term overload capacity is supported depending on design and cooling conditions, but continuous overload is not recommended.